Scribing instrument



y 1961 v s. E. PAVELEK 2,982,022

SCRIBING INSTRUMENT Filed June 16, 1959 Inventor SANDY E. PAVEL EK Maw- 2,982,022 I SCRIBING INSTRUMTENT Sandy Eugen Pavelek, 67 Barrymore Road, Scarboro, Ontario, Canada Filed June 16, 1959, Ser. No. 820,639

9 Claims. (Cl. 30- 1649) This invention relates to a scribing instrument for use in making silk screen cutouts and film scribing and cutting procedures for colour separation techniques in map making and like arts.

Heretofore scribing and cutting devices for colour separation methods using cutout techniques have required the operator to utilize a guided stylus or cutting knife working along a rule guiding edge or alternatively to move the stylus by careful free hand manipulation. Prior attempts to utilize a stylus or cutting knife during such free-hand or guided motion have resulted in complicated instrumentation efiectively obscuring the image being worked upon in such a manner that the actual operation of the stylus or cutting point may be difficult to observe during progress of the work.

It is the main object of this invention to provide a scribing instrument of simple construction.

It is a further object of the invention to provide a scribing instrument having a removable scribing head adapted to be replaced by a cutting head for separation cutout work.

With the foregoing and other objects in view the invention generally comprises a scribing instrument in the form of a supporting ring having three fixed legs thereon by means of which the supporting ring or body may be moved over a work surface at a fixed distance therefrom. A carrier member is supported within said body for adjustable axial motion therein effected by the operator to adjust the height thereof relative to the working surface. A freely rotatable tube is mounted axially of said body on bearings within said carrier and projects below the latter to mount a work head. The work head may be in the form of an efiectively transparent disc carrying a cutting scribe member having an eccentrically located cutting or scribing point thereon or alternatively may be in the form of a ring like member having a cutting or scribing knife extending inwardly therefrom on an adjustable mounting to provide for adjustable eccentricity of the working point, that is the cutting or scribing edge thereof. Preferably a lens and mounting therefor is supported above said tube to enable the operator to sight through the tube and onto the Working point as the latter traverses the working surface over which the supporting ring or body is moved during scribing or cutting operations.

Other objects of the invention will be appreciated from a study of the following specification taken into conjunction with the drawings in which:

Figure 1 is a perspective view illustrating the manner of use of the instrument of the invention;

Figure 2 is a cut-away perspective view of the instrument of the invention revealing a cutting head and knife carried thereby;

Figure 3 is an enlarged sectional detail of a preferred form of supporting a leg for the ring like supporting body of the instrument of the invention;

Figure 4 is an underside perspective View of the inatent ice strument of the invention illustrating a transparent scribing head removably fastened thereto.

In the drawings and as shown in Figure 1 the instrument 10 of the invention is caused to be moved by an operator such as on the path Y to traverse the working surface 11 of a sheet 12 to effect a cutting or scribing of the line 12a on the surface 11. This operation may be required for anyone of a number of purposes such as in colour separation techniques; map tracing; the scribing of lines in mask templet work, as for example 'to define contour lines and the like in map making and other uses. The present instrument will enable the operator to view the actual cutting or scribing action as well as the critical area being worked upon during traverse of the instrument. In addition, the depth of cut or scribe may be adjusted by the operator and maintained as will be evident from the features of the structure hereinafter disclosed in more detail.

i A preferred form of scribing and/or cutting instrument is shown in sectional detail in Figure 2 and comprises a supporting ring or body 13 of annular form adapted to be traversed over a working surface 11 on three supporting legs 14 each carrying a rotatable ball 15 at the lower extremity thereof. A carrier member 16 is rotatable within body 13 on the mutual threads 17. By this means the carrier member 16 may be adjusted axially to determine its height above the working surface 11 when the latter is engaged by each rotatable ball 15 of the fixed legs 14 of the body part 13 of the instrument 10. If desired the indicia 18 on body 13 may be spaced in radial measurement in relation to the pitch of the threads 17. Motion of the indicator marking 19 from one indicia line 20 to an adjacent indicia line 21 may represent a height adjustment of the order of one onethousandth of an inch, for example, to enable the operator to Work with precision on films or coatings of predetermined uniform thickness.

The carrier member 16 embodies an inner annular recess 22 adapted to receive a bearing structure 23 having a stationary part 24 clamped therein by the annular clamping plate 25 fastened thereto by screws 26. The inner ring 27 of the bearing 23 is freely rotatable on the bearing balls 28 within the stationary ring 24 and extends inwardly to the inner edges of the carrier member and clamping plate 25 thereof to support the tube structure 29 rigidly therein and for rotation therewith. r

The one end 30, being the upper end of tube 29 embodies an outwardly directed flange fitting or flange portion 31 having a downwardly extending seating ring part 32 adapted to seat on the upper surface 33 of the inner rotating ring 27, thus limiting the downwardly extension of the tube 29 through the inner ring in relation to the carrier member 16. The other end 34, being the lower end of tube 29, projects downwardly below the clamping plate 25 to mount a work head member 35 of annular form adapted to seat by its inner recess 36 into frictional engagement on the lower end of tube 29. While frictional engagement is suitable for most purposes it may be desirable to embody mounting screws 37 substantially as shown whereby member 35 may be rigidly fastened to the tube 29. Regardless of the specific structure adapted to effect the mounting function desired, cutting or scribing means 38 which may hereinafter be referred to as a cutting means or cutting member are suitably fastened to the ring 35 in eccentric location in respect to the instrument axis 39 as will be described in more detail hereinafter.

The cutter member mounting illustrated in Figure 2 is preferably adapted to support a cutting knife 40 of 1y mounted in carrier block 44 having a stud portion 45 extending into the socket 46 of member 35 and having a hole or bore 47 therein through which clamping screw 37 passes to rigidly secure the'same therein. The socket 46 is disposed at a different radial distance from the instrument axis 39 than the socket 48. Accordingly, the cutting blade 40 may be mounted by selection of the desired socket in member 35 to determine the eccentricity of the cutting point 41 thereof with respect to the instrument axis 39.

A modified form of work head member or fitting is illustrated in Figure 4 in which the work head 35 is adapted by its lower inwardly directed flange 49 to support a transparent plastic disc or lens 50 having a cutting or scribing member 51 centrally bonded therein and extending downwardly therefrom to provide an eccentrically located scribing or cutting point 52 spaced an eccentric distance d from the instrument axis 39. The member 51 may be bonded into the lens or plate 50 by cementing or the plastic may be cast thereabout to bond the same in situ.

In use, the operator sets the instrument onto the working surface 11 illustrated in Figure 1 as before described and rotates the carrier member 16 by manual engagement of the actuating post 53 thereon effecting rotation on threads 17 to bring the cutting tip of the cutting knife 40 or the scribing tip 52 of the cutting member 51 into the desired depth of engagement with the surface 11 or coating on such surface.

The operator is enabled to View the action of the cutting or scribing tip by sighting through the mounting tube 29. Preferably a magnifying lens 54 supported by fitting structure 55 removably seated on flange 56 of carrier member 16 provides sufficient magnification of the action of the cutting or scribing point for the practice of high precision work.

In order to avoid damage to the cutting or scribing point of the working tool, whatever specific form the latter may take, it is desired according to this invention that the operator apply downward pressure on the instrument to eifect a predetermined depth of cut. This function may be provided by simple structure evident in the modification of the leg structure for the body indicated by the enlarged sectional view of the modified form of leg 56a shown in Figure 3. As shown, the rotatable ball 57 is supported in a ball retaining socket 58 having retaining flanges 59. An excessive socket depth provides for vertical motion of the ball in the socket corresponding to the dimension h. A bore 60 extends upwardly from socket 58 to accommodate an internal compression spring 61 normally urging the ball 57 outwardly, the spring 61 being of such spring force that the weight of the instrument is adapted to be entirely supported by the springs of three such legs whereby additional pressure is required to be applied by the operator to cause the ball to seat fully within its socket in each leg. By this means the cutting depth of the knife may be adjusted by the operator while applying the necessary downward pressure to overcome spring force in the supporting legs as for cutting and scribing operations. Release of this downward pressure will then cause the cutting or scribing point to be raised free of the working surface to avoid inadvertent damage to the latter should the instrument be carelessly moved.

What I claim is:

1. A scribing instrument adapted to be traversed by an operator over a surface to effect scribing operations thereon and comprising in combination: a ring like body having a central axis; support means for said body traversibly supporting said body a fixed distance above a surface and disposing said axis at right angles to said surface; an open ended tube disposed co-axially within said body and concentric with the latter; bearing means rotatably supporting said tube within said body for rotation-about-sa-id-axis, said tube being freely rotatable during traversing motion of said body over said surface; a tool having -a point; and means rigidly fastened to said tube for supporting said tool and locating the point of said tool in a position of eccentricity with respect to said axis.

2. A scribing instrument adapted to be traversed by an operator over a surface to effect scribing operations thereon and comprising in combination: a ring like body having a central axis; support means for said body traversibly supporting said body a fixed distance above a surface and disposing said axis at right angles to said surface; an open ended tube disposed co-axially within said body and concentric with the latter; bearing means rotatably supporting said tube within said body for rotation about said axis, said tube being freely rotatable during traversing motion of said body over said surface; a tool having a point; means rigidly fastened to said tube for supporting said tool and locating the point of said tool in a position of eccentricity with respect to said axis; and a carrier member of ring like structure supporting said bearing means within said body.

3. A scribing instrument adapted to be traversed by an operator over a surface to effect scribing operations thereon and comprising in combination: a ring like body having a central axis; support means for said body traversibly supporting said body a fixed distance above a surface and disposing said axis at right angles to said surface; an open ended tube disposed co-axially within said body and concentric with the latter; bearing means rotatably supporting said tube within said body for rotation about said axis, said tube being freely rotatable during traversing motion of said body over said surface; a tool having a point; means rigidly fastened to said tube for supporting said tool and locating the point of said tool in a position of eccentricity with respect to said axis; a ring-like carrier member; and thread means rotatably supporting said carrier member within said body and adapted upon adjusting rotation of said carrier member relative to said body to effect axial motion of said tube therewith thereby to adjust contact and depth of engage ment of said point with said surface.

4. A scribing instrument adapted to be traversed by an operator over a surface to effect scribing operations thereon and comprising in combination: a ring like body having a central axis; support means for said body traversibly supporting said body a fixed distance above a surface and disposing said axis at right angles to said surface; an open'ended tube disposed co-axially within said bly supporting said tube within said body for rotation about said axis, said tube being freely rotatable during traversing motion of said body over said surface; a tool having a point; means rigidly fastened to said tube for supporting said tool and locating the point of said tool in a position of eccentricity with respect to said axis; and a sighting lens disposed co-axially on said body in a position available to the operator for direct viewing of the point of said tool during traverse of the latter over said surface.

5. A scribing instrument adapted to be traversed by an operator over a surface to effect scribing operations thereon and comprising in combination: a ring like body having a central axis; support means for said body traversibly supporting said body a fixed distance above a surface and disposing said axis at right angles to said surface; an open ended tube disposed co-axially within said body and concentric with the latter; bearing means rotatably supporting said tube Within said body for rotation about said axis, said tube being freely rotatable during traversing'motion of said body over said surface; a tool having a point; means rigidly fastened to said tube for supporting said tool and locating the point of said tool in a position of eccentricity with respect to said axis; and a shank portion on said tool extending between the point and the mounting therefore and effectively intersected by said axis whereby said point is disposed to trail traversing motion of said body over-the surface.

anemone 6. A scribing instrument adapted to be traversed by an operator over a surface to efiect scribing operations thereon and comprising in combination: a ring like body having a central axis; support means for said body traversibly supporting said body a fixed distance above a surface and disposing said axis at right angles to said surface; an open ended tube disposed co-axially within said body and concentric with the latter; bearing means rotatably supporting said tube within said body for rotation about said axis, said tube being freely rotatable during traversing motion of said body over said surface; a tool having a point; means rigidly fastened to said tube for supporting said tool and locating the point of said tool in a position, of eccentricity with respect to said axis; and depressible means normally raising said body from. said surface to disengage the said tool therefrom.

7. A scribing instrument adapted to be traversed by an operator over a surface to eifect scribing operations thereon and comprising in combination: a ring like body having a central axis; support means for said body traversibly supporting said body a fixed distance above a surface and disposing said axis at right angles to said surface; an open; ended tube disposed co-axially within said body and concentric with the latter; bearing means rotatably supporting said tube within said body for rotation about said axis, said tube being freely rotatable during traversing motion of said body over said surface; a tool having a point; means rigidly fastened to said tube for supporting said tool and locating the point of said tool in a position of eccentricity with respect to said axis; a carrier member of ring like structure supporting said bearing means within said body; and a sighting lens disposed coaxially on said body in a position available to the operator for direct viewing of the point of said tool during traverse of the latter over said surface.

8. A scribing instrument adapted to be traversed by an surface; an open ended tube disposed eo-axia lly within a tool having a point; means rigidly fastened to said tube for supporting said tool and locating the point of said tool in a position of eccentricity with respect to said axis; a carrier member of ring like structure supporting said bearing means within said body; and a shank portion on said tool extending between the point and the mounting therefore and effectively intersected by said axis whereby said point is disposed to trail traversing motion of said body over the surface.

9. A scribing instrument adapted to be traversed by an operator 'over a surface to effect scribing operations thereon and comprising in combination: a ring like body having a central axis; support means for said body traversibly supporting said body a fixed distance above a surface and disposing said axis at right angles to said surface; an open ended tube disposed co-axially within said body and concentric with the latter; bearing means rotatably supporting said tube within said body for rotation about said axis, said tube being freely rotatable during traversing motion of said body over said surface; a tool having a point; means rigidly fastened to said tube for supporting said tool and locating the working point of said tool in a position of eccentricity with respect to said axis; a carrier member of ring like structure supporting said bearing means within said body; and depressible means normally raising said body from said surface to dis engage the said tool therefrom.

References Cited in the file of this patent v UNITED STATES PATENTS Dentzler Nov. 21, 1944 2,735,177 Adams Feb. 21, 1956 2,735,178 Adams Feb. 21, 1956 2,805,475 Adams Sept. 10, 1957 2,810,960 Johnson et al Oct. 29, 1957 

